From U.S. Pat. No. 3,964.,457, it is known to vary the no-load speed of an internal combustion engine by adjusting the throttle flap. For this purpose, first, a throttle flap switch is connected to the throttle flap, indicating the no-load position of the throttle flap, and an electrically adjustable cam is provided, with the aid of which this no-load position and hence the position of the throttle flap can be varied. As can also be learned from the aforementioned patent, the cam is acted upon in accordance with the no-load position of the throttle flap and with the speed of the engine.
The disadvantage of the above-described known apparatus is that in the no-load situation a continuous variation of the cam and hence of the position of the throttle flap occurs, so that the no-load speed also continuously varies slightly. Such fluctuations in the no-load speed are undesirable, however, because they impede smooth operation of the engine.